How To Clean a Sprayer After Using Roundup: SOLVED

So you’ve taken time to read the instructions, followed the mixing and application directions to the letter, and spent all day painstakingly eradicating all the weeds from your yard only to find you need to clean your sprayer before you safely stow it away until next year! So I’m going to solve the question of how to clean a sprayer after using roundup…or any other garden weed killer.

The International Agency for Research on Cancer lists glyphosate as a probable carcinogenic. However, its carcinogenic effects are a controversial topic. The herbicide can also expose you to long-term health risks, such as reproductive issues, liver disease, and pregnancy risks.

Therefore, not only do you need to protect yourself whilst getting the job done, but you also need to clean your sprayer thoroughly after using Roundup to avoid further exposure. Here’s my straight-talking and no-fuss guide on how to clean a sprayer after using Roundup.

How Do You Get Rid of Old Weed Killers?

Various US states run household hazardous waste programs with at least two collection events per year. These programs offer residents an opportunity to safely dispose of RoundUp and other harmful chemicals.

For instance, Tennessee runs these events in the fall and spring to avoid harsh weather, while in California, there are various collection facilities in each city.

However, if you are a farmer or commercial pesticide user, you cannot use the standard household programs. Most states run clean sweep programs that handle the disposal of large quantities of pesticides and herbicides. Details of this program vary by state.

That said, you should try to avoid generating if at all possible by buying only enough Roundup for your garden. If you have a surplus, share it with your gardening friends or family. Make sure any remaining chemical goes to good use.

Can You Pour Roundup Down the Drain?

No. Pouring Roundup down a drain ends up contaminating the waterways. Even wastewater treatment plants cannot neutralize such chemicals, so the runoff will end up seeping into the ground. Eventually, in some way, it will end up back in your home, as we get our freshwater mostly from rivers and boreholes.

If there is no safe disposal method avoidable, dilute the Roundup and then spray it onto permitted plants. Check the label instructions to get this info.

How To Clean a Sprayer After Using Roundup?

Sprayers have two main parts: the tank and the nozzle. Whether it is a handheld or backpack sprayer, the cleaning process is somehow similar.

Backpack sprayers are the tools of choice if you have a big area to cover because they carry more content and are more flexible. Here is how you clean one.

How To Clean Roundup Out of Backpack Sprayer

Empty the tank. If you have a small surplus of herbicide inside, spray it on the plants again until the nozzle runs dry.

If you have a large amount of remaining liquid you will need to pour it into a container for disposal. Do this while still wearing protective clothing (at least gloves, mask and safety goggles), and clean the tank using a sponge, soap, and warm water.

Do not let the sprayer sit for a long time without cleaning. Wash it immediately after use to keep the chemical residues from building up on the tank surface.

How Do I Clean My Roundup Sprayer Nozzle?

While it is possible to clean the tank using a sponge, the nozzle has unreachable internal cavities. Therefore, you need to flush it and begin the process using hot soapy water.

Pour the water into the tank until halfway, then spray it all out of the nozzle. Consider spraying close to where you were applying the herbicide to avoid contaminating other areas.

Next, flush the system using an ammonia-based cleaning solution. You can make some by yourself, and it should have a ratio of about 3ml of ammonia to 380ml of water. Fill the tank halfway, then spray it out about five times to flush the wand and nozzle.

Leave the remaining solution in the tank overnight, then spray it all out the next day.

Rinse and spray with hot water again, then finish by cleaning the nozzle exterior using an old toothbrush. Remember to clean the hose and wand as well.

How Do You Neutralize Roundup in a Sprayer?

Cleaning & diluting with water helps reduce the toxicity of Roundup, but the best neutralizer is ammonia.

As described in the steps above, you should leave the ammonia solution in the tank overnight, which helps to break down the herbicide.

If you have the money, you can buy commercial tank cleaners and detergents which are more effective at breaking down water and oil-soluble herbicides compared to household detergents and chemicals.

Can You Leave Weed Killer in a Sprayer?

Yes, you can. However, it does depend on the amount of time you are leaving it there. If there is an interruption due to weather, it is okay to leave the chemicals in the tank, provided you resume spraying after a few hours. You only have to agitate the herbicide in the tank to mix up the chemicals.

However, leaving it for more than a few hours will lead to blockages. Heat and cold tend to make the Roundup clump up, forming a gel that clogs the nozzles and lines the tank.

The best practice is to measure or approximate the exact amount you need so that you spray everything in the tank and clean it at the end of the day.

If you have to continue spraying the next day, at least wash the tank using hot soapy water. Neutralize with ammonia once you have completed the spraying project.

Final Thoughts Cleaning Glyphosate From a Sprayer?

Glyphosate weed killers are super beneficial to farming and gardening, but you must handle them with care and with environmental safety in mind.

Whichever sprayer you use to apply Roundup, ensure you clean it the right way to ensure safety and long-lasting use.

Although these are the general cleaning and disposal directions, it is vital to check the manufacturer’s instructions to implement the best practices.